Seeing a second life for PVB from auto windshields

As plastics companies continue to invest in more sustainable practices, some are finding the cost of using recycled materials is the same or less costly than using virgin raw materials.

Materials like polyvinyl butyral, used as a safety interlayer in laminated glass since the 1930s, can be reclaimed from broken automotive windshields and laminated architectural glass, Jens Holmegaard, CEO and founder of alternative raw materials supplier Shark Solutions ApS, told Plastics News.

"The chemistry is very well known," he said. "You can recycle it again and again … and the virgin PVB is very expensive."

Cost is "through the roof" for companies looking to source material due to shortages, transportation and other supply chain issues, Holmegaard said.

"Normally, broken windshields would just go to a landfill and sit there for a million years," he said. "You can imagine that laminated glass does not decompose easily. The PVB interlayer, between the two layers of glass, [is] wasted."

Climate change-related events in the last couple of years have "proved to all responsible managers and politicians that we do need to make a shift in the way that we look at the world and our resources," Holmegaard said. "It makes no sense to keep digging out virgin raw materials … and just throwing away so much."

The Roskilde, Denmark-based company spent "many years and much money" to develop the technology and system to separate and recycle the glass from the PVB, which is then cleaned and turned into solid plastic pellets or a water-based ingredient that can go in paints, coatings and carpet backing, he said.

Shark Solutions hopes to diversify its thermoplastic elastomer application areas, he added.

Materials supplier Avient Corp. added two new injection moldable TPEs from its collaboration with Shark Solutions, which contain 25 percent post-consumer content and can be overmolded to polypropylene, an Aug. 19 news release said.

Avient helped to formulate the reprocessed PVB into its TPEs, which were developed in 45 to 55 Shore A durometers, the new reSound R grades.

The TPEs "offer similar performance properties to traditional TPEs and are suitable for many durable consumer products and grips, such as personal care items, lawn and garden tools, golf clubs and footwear," the release said. "Their performance properties also fit automotive applications that could benefit from vibration damping, such as doormats, door damping and glove boxes."

Shark Solutions reprocesses "well over" 10,000 tons per year, Holmegaard said. "But there's much more available out there. … There's plenty of feedstock.

"Thousands of tons of PVB," found in the inner layer of the windshields, are still potentially bound for landfills, the release added.

PVB is regionally recycled at Shark Solutions' two plants in U.S. and one in Belgium.

"We need to do much more local sourcing instead of shifting stuff around globally," Holmegaard said. "We're really looking forward to getting this [partnership] off ground."

The company has been selling the recycled PVB "for a while" but is "excited" to partner with Avient, he said, which has a global presence and is "seriously and really committed to sustainability."

"These material developments create an opportunity to help divert mountains of valuable resources from the waste stream and upcycle them into new products that offer excellent performance and value," Matt Mitchell, director of global marketing of specialty engineered materials at Avient, said in the release.

"Avient shares our vision to preserve limited natural resources for future generations through products that enhance performance and protect the environment," Holmegaard said.

"Being environmentally conscious is not more costly for the companies," he said. "But it does take a commitment to make a change and adapt product specifications, in some cases, adapt feedstock. … It's good for business, and it's good for the world."